Lead frame, optical module, and a method of optical module

ABSTRACT

Provided are a lead frame, an optical module, and a method of making the optical module. These can reduce the force applied to a ferrule from an encapsulating die even if the alignment accuracy required in the step of bonding an optical module principal portion mounted with the ferrule onto the lead frame is relaxed. The lead frame has an island portion for mounting the optical module principal portion such that the ferrule is aligned with a predetermined direction; and an island support portion, included within the plane including the lead frame, allowing the island to be displaced in a direction intersecting the predetermined direction.

This application is a divisional of U.S. application Ser. No.09/267,617, filed Mar. 15, 1999, patented U.S. Pat. No. 6,377,742.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lead frame applicable to aresin-encapsulated optical module, an optical module employing this leadmodule, and a method of making the optical module.

2. Related Background Art

Researches and developments are being made in optical modules in whichan optical fiber, a ferrule, and a semiconductor optical device aremounted on a substrate, bonded onto a lead frame, and thenresin-encapsulated by transfer molding. There have been no reports inconferences or the like concerning a mass production method in which ahighly reliable optical module can be made.

SUMMARY OF THE INVENTION

Such an optical module comprises an optical fiber, a ferrule, asemiconductor laser diode, a substrate, and a resin body. The substrateis formed with an optical fiber support groove for supporting theoptical fiber, and a ferrule support groove for supporting the ferrule.On the substrate, the optical fiber is provided in the optical fibersupport groove, the ferrule is provided in the ferrule support groove,and the semiconductor laser diode is provided so as to be opticallycoupled to the optical fiber. After this substrate is bonded on the leadframe, wire bondings are made. After the resulting assembly issubsequently resin-encapsulated, the lead frame is cut, and the leadsare bent. As a result, the finished optical module is provided.

FIG. 1 is a plan view of a lead frame that can be applied to such anoptical module. The lead frame 90 comprises an island 93 and supportportions 94. The above-mentioned substrate is mounted on the island 93.Each support portion 94 connects the island 93 to either a frame 91 or atie bar 92, thereby supporting the island 93. The support portions 94extend from three sides of the island 93 in the respective directionsperpendicular to their corresponding sides, thereby reaching either theframe 91 or tie bars 92.

In a method of making the optical module, an optical module principalportion mounted with the ferrule is bonded to the island. For resinencapsulating the optical module principal portion and the lead frame,the lead frame mounted with the optical module principal portion isplaced in an encapsulating die so as to be resin-encapsulated.

Having studied this optical module, the inventor has found the followingpoints.

Since the island is supported by the support portions extending alongthree respective directions, the island does not have a sufficientflexibility with respect to the outer frame of the lead frame. When thelead frame is placed in the encapsulating die, care must be taken sothat no force is applied from the encapsulating die to the ferrulemounted on the optical module principal portion. It is necessary thatthe lead frame is placed in the encapsulating die after the opticalmodule principal portion is correctly aligned with the lead frame andthen bonded to it. Otherwise, it is necessary that the optical moduleprincipal portion is correctly aligned with the lead frame on theencapsulating die. This procedure needs much time for aligning theoptical module principal portion.

It is an object of the present invention to provide a lead frame whichcan reduce the force applied to the ferrule from an encapsulating die,an optical module made with this lead frame, and a method of making thisoptical module.

The lead frame in accordance with the present invention is utilized formounting an optical module principal portion. The optical moduleprincipal portion includes an optical module substrate. Placed on thesubstrates are an optical fiber, a ferrule, and a semiconductor opticaldevice optically coupled to the optical fiber. The lead frame comprisesan island portion, a frame portion, and an island support portion. Theisland portion is provided so as to mount the optical module principalportion such that the ferrule aligns with a predetermined axis. Theframe portion is provided so as to support the island portion. Theisland support portion is provided so as to connect the island portionand the frame portion to each other, and has a plurality of bentportions. The island support portion extends from the island portion andbends at a plurality of positions, so as to reach the frame portion. Asa consequence, when the optical module principal portion isresin-encapsulated using an encapsulating die, the misalignment betweenthe ferrule mounted on the substrate and the encapsulating die can bereduced by the island support portion.

The lead frame in accordance with the present invention can furthercomprise a substrate support portion provided so as to support theoptical module principal portion mounted on the island portion. Thesubstrate support portion is separated from the island portion. Theisland portion has a notch, whereas the end of the substrate supportportion is positioned within the notch. Also, the lead frame inaccordance with the present invention can comprise a pair of substratesupport portions. The pair of substrate support portions can be arrangedsuch that the predetermined axis is provided between the pair ofsubstrate support portions.

Various kinds of arrangements can be applied to the island supportportion of the lead frame in accordance with the present invention asfollows. The island support portion can comprise a first part extendingfrom the island portion in a direction intersecting the predeterminedaxis, a second part extending from the first part along thepredetermined axis, and a third part extending from the second part in adirection intersecting the predetermined axis. Alternatively, the islandsupport portion can comprise a fourth part extending from the islandportion along the predetermined axis, a fifth part extending from thefourth part in a direction intersecting the predetermined axis, and asixth part extending from the fifth part along the predetermined axis.The island support portion can include a part thinner than the islandportion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a lead frame;

FIG. 2 shows an optical module substrate formed with grooves;

FIG. 3 shows the optical module substrate;

FIG. 4 shows the substrate during a step of mounting an optical devicethereon;

FIG. 5 is a view showing a step of providing the substrate with anoptical fiber;

FIG. 6A shows an optical module principal portion, FIG. 6B shows anoptical fiber secured to an optical fiber support groove, and FIG. 6Cshows a ferrule secured to a ferrule support groove;

FIG. 7 shows a step of assembling the optical module principal portionon a lead frame;

FIG. 8 shows a step of dropping a resin onto the optical moduleprincipal portion;

FIG. 9 is a plan view of a lead frame in accordance with the presentinvention;

FIG. 10 is a plan view of a lead frame in accordance with anotherembodiment of the present invention;

FIG. 11 is a plan view showing a lead frame in accordance with stillanother embodiment of the present invention;

FIG. 12 is a plan view showing the lead frame of FIG. 9 mounted with theoptical module principal portion of FIG. 6A;

FIG. 13 is a perspective view showing a transfer-molding die;

FIG. 14 is a perspective view showing the lead frame of FIG. 12 on whichthe transfer-molding die of FIG. 13 is provided;

FIG. 15 is a plan view showing the lead frame encapsulated with amolding resin;

FIG. 16 is a perspective view showing the finished optical module; and

FIG. 17 is a perspective view of another optical module principalportion to which the lead frame of the present invention is applicable.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be explained with reference tothe accompanying drawings. Parts identical or similar to each other willbe referred to with the identical numerals or letters if possible,without repeating their overlapping descriptions.

FIG. 2 is a view showing an optical module substrate. The substrate 2comprises a first region 2 a, a second region 2 b, and a third region 2c along a predetermined axis 3.

The first region 2 a is provided with a ferrule support groove 4 forsupporting a ferrule. The ferrule support groove 4 has two side faces 4a, 4 b for supporting the ferrule and a bottom face 4 c held betweenthese two side faces. This groove has a trapezoidal cross section. Thesecond region 2 b is provided with an optical fiber support groove 5 forsupporting an optical fiber. In the optical module substrate 2, theoptical fiber support groove 5 and the ferrule support groove 4 areformed on the same substrate 2.

Referring to FIG. 3, the substrate 2 is formed with a positioning groove9 and a connecting groove 10.

The substrate 2 has the positioning groove 9 provided so as to separatethe second region 2 b and the third region 2 c from each other and beable to position the optical fiber. The positioning groove 9 is disposedat one end of the optical fiber support groove 5 and intersects theoptical fiber support groove 5 at a predetermined angle, e.g., 90°.

The substrate 2 has the connecting groove 10 disposed so as to separatethe first region 2 a and the second region 2 b from each other. Theconnecting groove 10 is disposed between the optical fiber supportgroove 4 and the ferrule support groove 5. The connecting groove 10intersects the optical fiber support groove 4 and the ferrule supportgroove 5 at an angle of 90°, for example.

The third region 2 c has an optical device mount portion 6. FIG. 2 showsthe substrate 2 suitable for optically connecting a semiconductorlight-emitting device (11 in FIG. 4) to the optical fiber. Asemiconductor light-emitting device such as semiconductor laser isplaced at the optical device mount portion 6. For monitoring thesemiconductor laser, a monitor light-receiving device (12 in FIG. 4)such as photodiode can be provided. The optical device mount portion 6has electrodes 8 a, 8 b, 8 c, 8 d for the optical device.

The substrate 2 is also referred to as silicon bench when it is formedof a silicon substrate.

FIG. 4 is a view showing a step of mounting a semiconductor opticaldevice onto the substrate 2. The optical device is placed at the opticaldevice mount portion 6 of the substrate 2. This optical device can beoptically coupled to the optical fiber. The following explanation willrelate to a semiconductor laser (LD) 11 and a monitor photodiode (PD) 12mounted on the substrate as the semiconductor light-emitting device andsemiconductor light-receiving device, respectively.

The LD 11 is die-bonded to the optical device mount portion 6 of thesubstrate 2. The die-bonding is carried out after markers on the LD andthe substrate 2 are aligned with each other by use of image recognition.For achieving sufficient optical coupling to the optical fiber(single-mode optical fiber: SMF) disposed in the optical fiber supportgroove 4, a positioning tolerance of 2 μm is required.

Subsequently, the PD 12 is die-bonded on the optical device mountportion 6 of the substrate 2. The die bonding is carried after a markeron the PD and markers 7 a, 7 b on the substrate 2 are aligned with eachother by use of image recognition. A positioning tolerance of about 10μm is required for this step.

FIG. 5 is a view showing a step of securing an optical fiber 16 to thesubstrate 2. The optical fiber is placed in the optical fiber supportgroove 5 of the substrate 2 and then is secured thereto by means of asecuring member 18. For this purpose, a UV-curing resin is dropped ontothe substrate 2 so as to avoid the optical fiber support groove 5,thereby forming resin members 19 a. The optical fiber 16 is disposed inthe optical fiber support groove 5 and then is covered with the securingmember 18. The securing member 18 has a groove 18 a for accommodatingthe optical fiber 16, and a bonding surface 18 b provided so as to facethe substrate 2. The optical fiber 16 is supported by three flat facesconsisting of the two side faces of the optical fiber support groove 5and the bottom face of the groove 18 a of the securing member 18. Thesecuring member 18 is formed from a material that can transmitultraviolet light therethrough, e.g., quartz.

FIG. 6A is a view showing a step of securing a ferrule 17. The ferrule17 is placed in the ferrule support groove 4. UV-curing resin members 19b are also applied to the regions between the side face of the ferrule17 and the first region 2 a of the substrate 2.

Upon irradiation with ultraviolet light, the optical fiber 16 is securedby the securing member 18 and the resin members 19 a, whereas theferrule 17 is secured by the resin members 19 b. As a consequence, anoptical module principal portion 1 is accomplished.

Since the UV-curing resin is used for securing the ferrule 17 and thesubstrate 2 to each other, the easier handling of the optical moduleprincipal portion is provided after this step. In place of the UV-curingresin, a thermosetting resin can be used as well.

In FIG. 6B, the optical fiber 16 is secured to the optical fiber supportgroove 5 while coming into contact therewith at two side faces 5 a, 5 b.In FIG. 6C, the ferrule 17 is secured to the ferrule support groove 4while coming into contact therewith at two side faces thereof.

FIG. 7 shows a step of assembling the optical module principal portion 1on a lead frame 60. The optical module principal portion 1 is bonded toan island portion 63 of the lead frame 60. After the island portion 63is coated with silver paste, the optical module principal portion 1 ismounted on the island portion 63. For example, the silver paste isheated under such a condition as 180° C. for 20 minutes, so as to bethermally cured. Prior to this bonding, the lead frame 60 and theferrule 17 are aligned with each other.

Thereafter, the optical module principal portion 1 and the lead frame 60are wire-bonded.

FIG. 8 shows a potting step in which a resin is dropped onto the opticalmodule principal portion 1. It is desirable that the potting is effectedat two locations of the optical module principal portion.

One of the locations lies in the region where the LD 11, PD 12, and theend portion of the optical fiber 16 optically coupled to the LD 11 areprovided. A potting resin member 39 a is transparent to light generatedby the LD 11.

The other lies in the region where the optical fiber 16 exposed on thesubstrate 2 is provided. Covering the optical fiber 16 with a pottingresin member 39 b can reduce the influence of contraction at the time ofthe hardening of the molding resin used in transfer molding.

Thereafter, after the encapsulation with a resin body 52 in transfermolding and the formation of leads, an optical module 54 as shown inFIG. 16 is accomplished.

Now referring to FIG. 9, the lead frame in accordance with the presentinvention will be described. FIG. 9 is a plan view of the lead frame 60on which the optical module principal portion 1 shown in FIG. 6A can bemounted.

The lead frame 60 comprises an outer frame 61, tie bars 61 e, 61 f,inner leads 62 a, outer leads 62 b, an island portion 63, and islandsupport portions 64, 65, 66. The outer frame 61 has a top rail 61 a, abottom rail 61 b, and side rails 61 c, 61 d. The outer frame 61 isprovided with two positioning holes 69, at their respective locations,available for aligning the lead frame 60 with an encapsulating die. Theouter frame 61 constitutes a frame portion. The frame portion caninclude the tie bars 61 e, 61 f. The frame portion can also include theinner leads 62 a and outer leads 62 b.

The lead frame 60 has a plurality of inner leads 62 a. In the lead frame60 shown in FIG. 9, the inner leads 62 a are provided so as to facethree sides of the island portion 63. These three side faces areoriented in one direction along the predetermined axis 51 and otherdirections orthogonal to a predetermined axis 51, respectively. Theinner leads 62 a are wire-bonded by conductive wires to theircorresponding electrodes on the optical module principal portion 1mounted on the island 63, so as to be electrically connected with theoptical module principal portion 1. The inner leads 62 a are supportedby the tie bars 61 e, 61 f.

The lead frame 60 has a plurality of outer leads 62 b. The plurality ofouter leads 62 b are disposed so as to correspond to the respectiveinner leads 62 a. In the lead frame 60 shown in FIG. 9, the outer leads62 b extend in directions orthogonal to the predetermined axis 51. Theouter leads 62 b start from the tie bars 61 e, 61 f, and then extend ina direction from the tie bars 61 e, 61 f toward the outer frames 61 a,61 b so as to reach the outer frame.

The optical module principal portion 1 is mounted on the island portion63 such that the end face of the ferrule 17 mounted on the opticalmodule principal portion 1 is oriented in the direction of thepredetermined axis 51 (the positive direction of X axis in FIG. 9). Theisland portion 63 has the island support portions 64 (64 a, 64 b, 64 c,64 d, 64 e), 65 (65 a, 65 b, 65 c, 65 d, 65 e), 66 (66 a, 66 b, 66 c, 66d, 66 e) extending from three side faces thereof, respectively.

The island support portions 64, 65, 66 have deformation parts which aredisposed such that the position of the island portion 63 can bedisplaced in directions (e.g., Y directions in FIG. 9) intersecting thepredetermined axis 51 within the plane including the island portion 63.The island support portions 64, 65 are disposed at two island sidesoriented in directions intersecting the predetermined axis 51. Theisland support portion 66 is disposed at one of island sides oriented inthe directions of the predetermined axis 51. The island support portions64, 65, 66 reach the outer frame 61 d or the tie bars 61 e, 61 f, so asto support the island portion 63. The deformation parts are elasticallydeformed or flexed, thereby making the position of the island portion 63movable in directions orthogonal to the predetermined axis 51 in theplane including the lead frame 60.

Each of the island support portions 64, 65, 66 can comprise bent partswhich are bent at two or more positions.

When the bent parts are provided at two positions, the followingstructure can be realized: the island support portion can comprise afirst part extending along the predetermined axis 51, and second andthird parts extending in directions intersecting the predetermined axis51, both ends of the second part being provided with the second andthird parts, respectively; the island support portion can comprisefourth and fifth parts extending along the predetermined axis 51, and asixth part extending in a direction intersecting the predetermined axis51, both ends of the sixth part being provided with the fourth and fifthparts, respectively.

The X coordinates of the positions at which the island support portions64, 65 connect with the tie bars 61 e, 61 f differ from those of thepositions at which they connect with the island 63. The Y coordinates ofthe positions at which the island support portion 66 connects with theouter frame 61 a to 61 d also differ from the Y coordinate of theposition at which the island support portion 66 connects with the island63. Such positional differences make it easy to provide the islandsupport portions 64, 65, 66 with bent parts without restricting thearrangement of inner leads.

In the example shown in FIG. 9, a first portion 66 a and second portions64 b, 65 b function as deformation parts. Preferably, the first portion66 a is narrower and longer than the other parts of the island supportportion 66. Preferably, the second portions 64 b, 65 b are narrower andlonger than the other parts of the island support portions 64, 65.

The island 63 is supported by the island support portions 64, 65, 66. Asa consequence, when the ferrule 17 is placed at the ferruleaccommodation portion (42 in FIG. 12) of the encapsulating die so as tobe resin-encapsulated, the deformation parts are deformed in response tothe misalignment between the ferrule 17 mounted to the optical moduleprincipal portion 1 and the ferrule accommodation portion 42. Thisdeformation can absorb the positional deviation between the ferrule 17and the ferrule accommodation portion (42 in FIG. 12). The inner stresscaused by this positional deviation would not remain in theencapsulating resin body.

The lead frame 60 shown in FIG. 9 relates to the case where three sidesof the island 63 are provided with the island support portions 64, 65,66, respectively. The positions at which the island support portions arearranged should not be, however, restricted to the examples shown inFIG. 9. For example, the island support portions can be provided at onlytwo sides of the island portion 63 that are oriented in directionsorthogonal to a predetermined axis.

Preferably, the island support portions are made thinner than the island63. The thinner island support portions can be deformed more easily. Amethod of thinning the island support portions 64, 65, 66 is as follows:the lead frame 60, covered with an etching mask except for parts to bethinned, is exposed for a predetermined period of time to a solutioncapable of chemically etching the material of lead frame 60.

FIGS. 10 and 11 show other embodiments of the lead frame in accordancewith the present invention. In FIGS. 10 and 11, parts having the samefunctions as those of the lead frame 60 shown in FIG. 9 are referred towith the identical numerals or letters, without repeating theirdescriptions.

The lead frame 70 shown in FIG. 10 comprises only one island supportportion 66. The island support portion 66 has a deformation partprovided so as to make the island portion 63 displaceable in directions(Y directions in FIG. 10) orthogonal to the predetermined axis 51. Theisland support portion 66 is disposed at an island side intersecting thepredetermined axis 51 (the positive x direction in FIG. 10).

The lead frame 70 comprises substrate support portions 67 a, 67 b. Thesubstrate support portions 67 a, 67 b extend toward the island 63 fromthe tie bars 61 e, 61 f, respectively. The substrate support portions 67a, 67 b can assist in supporting the optical module principal portion 1mounted onto the island portion 63. Together with the island supportportion 66, the substrate support portions 67 a, 67 b support theoptical module principal portion 1. The island portion 63 comprises apair of depressions 63 b. The front ends of the substrate supportportions 67 a, 67 b are positioned within the depressions 63 b of theisland 63, respectively.

When the front end parts of the substrate support portions 67 a, 67 bcome into contact with the bottom face of the optical module principalportion 1, the substrate support portions 67 a, 67 b support the opticalmodule principal portion 1 together with the island portion 63. Thesubstrate support portions 67 a, 67 b prevent the island support portion66 supporting the island 63 from flexing due to the load of the opticalmodule principal portion and thereby dislocating the island portion 63from the plane including the lead frame 70.

FIG. 11 is a plan view showing the lead frame in accordance with anotherembodiment of the present invention. Referring to FIG. 11, the leadframe 80 comprises a pair of island support portions 68 (68 a, 68 b, 68c). The pair of island support portions 68 (68 a, 68 b, 68 c) havedeformation portions provided so as to make the island 63 movable indirections (Y directions in FIG. 11) orthogonal to the predeterminedaxis 51. The pair of island support portions 68 are disposed at theopposite ends of one side of the island portion 63, respectively.

The island support portions 68 prevent the dislocation of the island 63from the plane including the lead frame 80 due to the load of theoptical module principal portion 1. FIG. 11 shows the lead frame 80having the substrate support portions 67 a, 67 b. The substrate supportportions 67 a, 67 b can be, however, omitted if the island portion 63can fully be supported by the island support portions 68 attachedthereto. When no substrate support portions 67 a, 67 b are provided, thearrangement of inner leads 62 a is restricted thereby.

As described in the foregoing, since the island support portions 64, 65,66, 68 are provided, the positional deviation between the ferrule 17mounted on the optical module principal portion 1 and the ferruleaccommodation portion of the encapsulating die (42 in FIG. 12) can beabsorbed by the island support portions when the ferrule 17 is placed inthe ferrule accommodation portion (42 in FIG. 13).

A method of making an optical module using the lead frame in accordancewith an embodiment of the present invention will now be explained indetail with reference to FIGS. 12 to 16.

Referring to FIG. 12, the optical module principal portion 1 is mountedon the island portion 63 such that the ferrule 17 aligns with thepredetermined axis 51 of the lead frame 60. The optical module principalportion 1 is positioned on the lead frame 60 such that the ferrule 17 isaccommodated in the ferrule accommodation portion (42 in FIG. 13) whenthe lead frame 60 is placed in the encapsulating die. After the mountinglocation of the optical module principal portion 1 is determined, theoptical module principal portion 1 is bonded onto the island portion 63.

Subsequently, the lead frame 60 including the optical module principalportion 1 bonded thereon is placed in the encapsulating die. Thisplacement has already been described with reference to FIGS. 7 and 8.

FIG. 13 is a perspective view of the lower encapsulating die 40. The die40 comprises pins 41 for aligning with the lead frame 60. On thelead-frame mounting surface 43 of the die 40, the ferrule accommodationportion 42 and a cavity portion 45 are disposed. The ferruleaccommodation portion 42 accommodates the ferrule 17 mounted onto theoptical module principal portion 1 when the lead frame 60 is mounted onthe surface 43. The cavity portion 45 defines the form of the resin bodyof the optical module provided under the lead frame surface. Theencapsulating resin for resin-molding is introduced into the cavityportion 45 from an injection gate portion 47.

Referring to FIG. 14, the lead frame 60 is mounted on the die 40 suchthat the positioning pins 41 of the die 40 are inserted into thealignment holes 69. Simultaneously with this positioning, the ferrule 17is accommodated in the ferrule accommodation portion 42. Even if theoptical module principal portion 1 is slightly dislocated in therightward or leftward direction of the ferrule 17 with respect to thelead frame 60, such dislocation can be absorbed by the island supportportions 64, 65, 66. As a consequence, providing the island supportportions 64, 65, 66 can reduce the force applied to the ferrule 17 evenwhen it is accommodated in the ferrule accommodation portion 42 of thedie 40.

After the lead frame 60 and the optical module principal portion 1 aremounted on the lower die 40, the upper die (not depicted) is assembledthereto. The encapsulating resin is injected from the injection gate 47and cured, whereby a resin body is formed.

FIG. 15 is a plan view showing the resin body 52 and the lead frame 60.The inner leads 62 a extend in directions orthogonal to thepredetermined axis 51 and are encapsulated within the encapsulatingresin body 52. The island support portions 64, 65 extend from the tiebars 61 e, 61 f, respectively so as to be contained within theencapsulating resin 52. The island support portions 66 extend from theouter frame 61 d of the lead frame so as to be encapsulated within theencapsulating resin 52.

After the resin molding, the tie bars 61 e, 61 f, the island supportportions 64, 65, 66, and the outer leads 62 b are cut at predeterminedpositions, and the outer leads 62 b are shaped.

FIG. 16 shows the finished optical module 54. Referring to FIG. 16, theshaped outer leads 62 b and the cut end 65 f of the island supportportion 65 are shown. In the optical module 54 shown in FIG. 16, sincethe tie bars 61 e, 61 f are cut, the outer leads 62 b are electricallyisolated from each other and from the island support portions 64, 65,66. Providing the island support portions 64, 65, 66 would not affectthe electric characteristics of the finished optical module 54.

An optical module principal portion 56 in accordance with anotherembodiment of the present invention will now be explained with referenceto FIG. 17. The optical module principal portion 56 corresponds to theoptical module principal portion 1 shown in FIG. 6A. The lead frame,optical module, and method of making the optical module in accordancewith the present invention are also applicable to the optical moduleprincipal portion 56 as described hereinafter.

Referring to FIG. 17, the substrate 57 comprises a base 57 a and aplatform 57 b. The platform 57 b is mounted on the base 57 a. The base57 a has a first region 57 c thereon. The platform 57 b has a secondregion 57 d and a third region 57 e along a predetermined axis 3. Thefirst region 57 c is provided with a ferrule support groove 58 forsupporting a ferrule. The second region 57 d is provided with an opticalfiber support groove 5 for supporting an optical fiber.

The optical fiber support groove 5 and the ferrule support groove 58 arecentered at the predetermined axis 3. Since the substrate 57 is similarto the substrate 2 of FIG. 3 except for these points mentioned above,further detailed explanation will be omitted.

In the lead frame in accordance with the present invention, as explainedin detail in the foregoing, the island support portion allows theposition of the island, provided for mounting the optical moduleprincipal portion, to be displaced in a direction intersecting theferrule axis. When the lead frame is placed in the encapsulating die soas to be resin-encapsulated, the stress caused by the positionaldeviation can be absorbed by the island support portion. Applying theselead frames to optical modules provides the optical modules in which theinner stress of the resin body is decreased.

What is claimed is:
 1. A lead frame for mounting an optical moduleprincipal portion; said optical module principal portion including asemiconductor optical device, an optical fiber optically coupled to saidsemiconductor optical device, and a ferrule in which said optical fiberis inserted; said lead frame comprising: a frame portion; an islandportion provided so as to mount said optical module principal portionsuch that said ferrule is aligned with a predetermined axis; an islandsupport portion, bent at a plurality of positions, connecting saidisland portion to said frame portion; further comprising a substratesupport portion provided so as to support said optical module principalportion mounted on said island portion, said substrate support portionbeing separated from said island portion; wherein said island portionhas a side face with a notch; and wherein an end of said substratesupport portion is positioned at said notch.
 2. The lead frame accordingto claim 1, wherein the island support portion has a part thinner inthickness than the island portion.
 3. A method of fabricating an opticalmodule in which an optical module principal portion including an opticalfiber, a ferrule in which the optical fiber is inserted, and asemiconductor optical device provided so as to be optically coupled tothe optical fiber is encapsulated with an encapsulating resin; themethod comprising the steps of: mounting the optical module principalportion on the lead frame according to claim 1; placing the lead framemounted with the optical module principal portion to an encapsulatingdie such that the ferrule is provided in a ferrule accommodation portionof the encapsulating die; and resin-encapsulating the lead frame and theoptical module principal portion using the encapsulating die.
 4. Amethod of fabricating an optical module in which an optical moduleprincipal portion including an optical fiber, a ferrule in which theoptical fiber is inserted, and a semiconductor optical device providedso as to be optically coupled to the optical fiber is encapsulated withan encapsulating resin; the method comprising the steps of: mounting theoptical module principal portion on the lead frame according to claim 2;placing the lead frame mounted with the optical module principal portionto an encapsulating die such that the ferrule is provided in a ferruleaccommodation portion of the encapsulating die; and resin-encapsulatingthe lead frame and the optical module principal portion using theencapsulating die.
 5. An optical module fabricated by the methodaccording to claim
 3. 6. An optical module fabricated by the methodaccording to claim
 4. 7. A lead frame for mounting an optical moduleprincipal portion, the optical module principal portion including asemiconductor optical device, an optical fiber optically coupled to thesemiconductor optical device, and a ferrule into which the optical fiberis inserted; the lead frame comprising: a frame portion; an islandportion having a mounting face extending along a predetermined plane,the island portion having a first edge, the island portion having anopening in the first edge of the mounting face, and the island portionbeing provided so as to mount the optical module principal portion suchthat the ferrule is aligned with a predetermined axis; an island supportportion, bent at a plurality of positions, connecting the island portionto the frame portion; a substrate support portion, having an end thereofpositioned in the opening, provided so as to support the optical moduleprincipal portion mounted on the island portion, the substrate supportportion being separated from the island portion in the opening, theopening being capable of receiving the end of the substrate supportportion therein.
 8. A method of fabricating an optical module in whichan optical module principal portion including an optical fiber, aferrule in which the optical fiber is inserted, and a semiconductoroptical device provided so as to be optically coupled to the opticalfiber is encapsulated with an encapsulating resin; the method comprisingthe steps of: mounting the optical module principal portion on the leadframe according to claim 7; placing the lead frame mounted with theoptical module principal portion to an encapsulating die such that theferrule is provided in a ferrule accommodation portion of theencapsulating die; and resin-encapsulating the lead frame and theoptical module principal portion using the encapsulating die.
 9. Anoptical module fabricated by the method according to claim 8.